Questions: Use the standard normal distribution or the t-distribution to construct a 99% confidence interval for the population mean. Justify your decision. If neither distribution can be used, explain why. Interpret the results. In a recent season, the population standard deviation of the yards per carry for all running backs was 1.29. The yards per carry of 25 randomly selected running backs are shown below. Assume the yards per carry are normally distributed. Which distribution should be used to construct the confidence interval? A. Use a normal distribution because n<30, the data are normally distributed and σ is unknown. B. Use a normal distribution because σ is known and the data are normally distributed. C. Use a t-distribution because n<30 and σ is unknown. D. Use a t-distribution because n<30 and σ is known. E. Cannot use the standard normal distribution or the t-distribution because σ is unknown, n<30, and the data are not normally distributed.

Transcript text: Use the standard normal distribution or the $t$-distribution to construct a $99 \%$ confidence interval for the population mean. Justify your decision. If neither distribution c be used, explain why. Interpret the results. In a recent season, the population standard deviation of the yards per carry for all running backs was 1.29 . The yards per carry of 25 randomly selected running bacl are shown below. Assume the yards per carry are normally distributed. Which distribution should be used to construct the confidence interval? A. Use a normal distribution because $n<30$, the data are normally distributed and $\sigma$ is unknown. B. Use a normal distribution because $\sigma$ is known and the data are normally distributed. C. Use a t-distribution because $\mathrm{n}<30$ and $\sigma$ is unknown. D. Use a t-distribution because $\mathrm{n}<30$ and $\sigma$ is known. E. Cannot use the standard normal distribution or the $t$-distribution because $\sigma$ is unknown, $\mathrm{n}<30$, and the data are not normally distributed.